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Home , Hawaiian duck, Laysan, Laysan duck, Lisianski Island

Hawaiian Conservation Action Plan

Focal : Duck ( laysanensis)

Synopsis: The is a small, primarily nocturnal and terrestrial duck that is restricted to the small islands of Laysan and Midway. It formerly was more widespread on the larger . The Midway population was created by translocations from Laysan in 2004 and 2005. Rising sea level, increasing storm surge, and lower precipitation associated with global climate change are expected to have serious impacts on the low-lying islands where this species occurs. Occasional outbreaks of avian botulism can cause high mortality. The primary conservation actions are preventing predators and other alien species from becoming established on these remote islands, managing habitat to provide adequate foraging and nesting sites, and establishing populations on additional islands by translocation.

Male Laysan Duck, Midway. Photo Eric VanderWerf Created wetland, Midway. Photo Eric VanderWerf

Geographic region: Northwestern Hawaiian Islands Group: Water Federal Status: Endangered State status: Endangered IUCN status: Conservation score, rank: 17/20, At-risk Watch List 2007 Score: Red Laysan Ducks feeding on brine flies around the hypersaline Climate Change Vulnerability: High lake on Laysan. Photo Cameron Rutt

Population Size and Trend: On Laysan, the most recent (2010) population estimate was 434±72 birds (Reynolds et al. 2011), but estimates have fluctuated from 322-688 over the last several decades (USFWS 2004). The population trend on Laysan is thought to be stable, but it has been difficult to determine due to the fluctuations. On Midway, 42 birds were translocated in two cohorts from Laysan in 2004 and 2005. The population on Midway increased rapidly to 473 (95% CI 439–508) in 2010 (Reynolds et al. 2012), though it has declined to around 300 after botulism outbreaks and the 2011 Japan tsunami (USFWS unpubl. data). Laysan Ducks have been kept in captivity since 1957, but most captive birds are not considered useful for reintroduction purposes because of concerns about the spread of disease and genetic introgression from hybridization with other waterfowl species in captivity (Reynolds and Kozar 2000).

Range: The Laysan Duck currently is found only on Laysan Island and , which are located in the Northwestern Hawaiian Islands (NWHI). The ducks use most of each island,

Laysan Duck profile - 1 October 2012

Hawaiian Action Plan

but both islands are very small; Laysan is 414 hectares (1,023 acres) in size, and Midway encompasses 596 hectares (1,473 acres; Krause et al. 2012). Even with the establishment of a second population on Midway, the Laysan Duck is thought to have the smallest range of any waterfowl species in the world, less than 10 km2. Laysan Ducks were still extant on Lisianski, also in the NWHI, as late as 1844 (Olson and Ziegler 1995). and subfossil evidence indicates that Laysan Ducks were widespread in the Hawaiian Islands prior to the arrival of (Rattus spp.) and occurred on Hawai‘i, Moloka‘i, O‘ahu, , and Kaua‘i (USFWS 2004).

Essential Biology: The Laysan Duck is a small (420-500 g) brownish duck wing orange legs and a white patch around the eye. The bill is greenish in males and orange in females. The amount of white on the head increases with age (Moulton and Marshall 1996). Laysan Ducks are unusual among waterfowl in being largely nocturnal and terrestrial. They forage primarily at night and rarely fly, preferring to walk. They exhibit several adaptations to a largely terrestrial lifestyle, including longer legs, shorter wings, fewer primary feathers, and reduced flight muscles (Moulton and Marshall 1996). Because they nest on the ground and tend to freeze rather than flush, Laysan Ducks are vulnerable to by mammals and today occur only on predator- free islands. The habitat requirements of the Laysan Duck include dense vegetated cover for nesting, a year-round prey base, and a source of fresh water (USFWS 2004). They use all available habitats on Laysan and Midway, including upland vegetation, ephemeral wetlands, freshwater seeps, mudflats, the hypersaline lake, and coastal areas. Laysan Ducks feed on terrestrial and wetland , algae, and seeds (USFWS 2004). Historical and paleoecological evidence suggests this species was a habitat generalist and occurred in a wide range of habitats. On high elevation islands, Laysan Ducks once were found in both coastal wetland and upland forests. The clutch size is small for a duck, averaging 3.8 eggs (Moulton and Marshall 1996). The chicks are precocial and can walk and swim almost immediately after hatching, but they follow the female to learn how and where to feed. Ducklings have more restrictive habitat requirements than adults because of their higher nutritional needs for growth and initial inability to process salt water. Duckling activities therefore are concentrated around sources of fresh water with nearby cover and high prey densities. The female provides almost all parental care, but breeding pairs exhibit long-term pair bonds (Reynolds et al. 2009). Laysan Ducks molt all of their flight feathers simultaneously, usually in July-August, causing them to become flightless

Laysan Duck profile - 2 October 2012

Hawaiian Bird Conservation Action Plan

for several weeks until the new feathers have grown in, during which time they are even more vulnerable to predation. Annual adult survival is high; survival of released birds on Midway was 0.65±0.08 (Reynolds et al. 2012), but juvenile survival is low (10-30%; USFWS 2002).

Primary Threats:  Small population size and range. Small populations with limited ranges are especially vulnerable to a variety of natural processes. Fluctuations in demographic parameters such as survival and reproduction can cause population declines and even extinction. The Laysan Duck’s limited range exacerbates the risk of extinction due to catastrophes such as droughts, tsunamis, severe storms, and disease epizootics. Loss of genetic variation is more likely in small populations, potentially limiting adaptation to changing conditions, although there is no evidence of inbreeding depression in Laysan Ducks so far.  Habitat loss and degradation. On Laysan, filling of the hypersaline lake by invasive wetland plants and declining precipitation during drought are concerns given the importance of the lake as foraging habitat. On Midway, some of the freshwater wetlands created for ducks were inundated with salt water and physically damaged by the Japan tsunami in March 2011. Most of these wetlands have recovered to near pre-tsunami levels after being pumped and salinity is steadily dropping. These wetlands continue to be vulnerable to saltwater incursions from high wave events and rising sea level, requiring periodic maintenance including removal of alien mosquito fish (Gambusia affinis) and preventing algae and plants from filling the wetlands.  Non-native predators. Laysan Ducks disappeared from the main Hawaiian Islands 800– 900 years ago after rats were introduced. Laysan and Midway, where the Laysan Duck is currently found, are free of non-native mammalian predators but accidental introduction of predators to Midway and Laysan is a potential threat. However, the long-term recovery strategy for the species calls for re-establishment of populations on the larger, high-elevation Hawaiian Islands, all of which are inhabited by a variety of non-native predators. Establishment of such populations will require protecting them from predators including feral dogs (Canis familiaris), feral cats (Felis silvestris), small Indian mongooses (Herpestes auropunctatus), rats (Rattus spp.), Cattle Egrets (Bulbulcus ibis), Barn Owls (Tyto alba), and bullfrogs (Rana catesbeiana). These predators are pervasive throughout the islands, but mongooses are not established on , , or .  Non-native invasive plants. Several species of invasive alien plants can alter habitat structure and decrease its value for Laysan Ducks. On Laysan, the non-native grass Cenchrus echinatus is highly invasive and can crowd out the native bunch grass , which is the preferred nesting substrate for Laysan Ducks. Eradication of this invasive grass was expensive and required 10 years of year-round effort. Pluchea indica is a wetland invasive shrub that degrades foraging habitat on Laysan and accelerates wetland filling.  Avian diseases. Avian botulism has occurred in Laysan Ducks on Midway and a severe outbreak in August 2008 caused the death of 181 ducks (Work et al. 2010). Botulism is a paralytic disease caused by ingestion of a toxin produced by the bacterium Clostridium botulinum, which thrives under anaerobic conditions in warm water with decomposing vegetation and carcasses. Birds can be treated and vaccinated if detected early. Removing carcasses of dead birds helps to reduce the severity of the outbreak. Wetland

Laysan Duck profile - 3 October 2012

Hawaiian Bird Conservation Action Plan

exclusion and water control structures have been proposed as additional methods of reducing the impact of outbreaks and possibly controlling the environmental conditions that can foster botulism. Mortality has been documented on Laysan due to drought, emaciation, and infestation by the Echinurea uncinata (Work et al. 2004).  Global climate change. Climate change and associated sea-level rise caused by thermal expansion of ocean water and melting of ice sheets is a serious long-term threat to all birds on atolls in the Northwestern Hawaiian Islands, including the Laysan Duck. Recent projections estimate a rise in sea level of 1-2 meters by the end of the 21st century (Vermeer and Rahmstorf 2009). The mean elevation of Laysan is 3.8 meters (12 feet) and the mean elevation of Sand Island on Midway is only 2.5 meters (8 feet). Rising sea level and storm surge are predicted to result in substantial losses of foraging and nesting habitat for the Laysan Duck caused by inundation, physical damage, and incursions of salt water into freshwater wetlands (Berkowitz et al. 2012, Krause et al. 2012). Other predicted results of climate change in the Hawaiian Islands include rising temperatures and declining precipitation, both of which could facilitate botulism outbreaks and Echinuria uncinata nematode infestation (Work et al. 2004, 2010).

Conservation Actions to Date: The Laysan Duck was federally listed as endangered in 1967 (USFWS 2004). Conservation actions have focused on maintaining the population on Laysan and creating a new population on Midway. Management actions conducted by the USFWS on Laysan have included removal of invasive alien plants such as Cenchrus echinatus and Pluchea indica, restoration of native plant species, and biosecurity to prevent introduction of additional alien plants and . The Laysan Duck population on Midway was created by translocation of 42 birds in two cohorts from Laysan in 2004 and 2005 (Reynolds and Klavitter 2006, Reynolds et al. 2008). Management conducted by the USFWS for Laysan Ducks on Midway has included enhancement and creation of freshwater wetlands, responding to outbreaks of avian botulism, and monitoring movements, habitat use, and demography. A substantial amount of research has been conducted on the Laysan Duck in preparation for translocations and to monitor populations, primarily by the U.S. Geological Survey Biological Resources Division Pacific Islands Ecosystem Research Center, including habitat use, home range size, survival and causes of mortality, nesting phenology and behavior, demography and population dynamics, diseases, and vulnerability to climate change (see references).

Planning/Research Needs:  Complete translocation plans for sites deemed suitable, particularly Lisianski, Kure, and Kaho’olawe (see USFWS 2004 for more details on site suitability assessments).  Assess options for re-establishing a breeding population of Laysan Ducks on Kaua’i, O’ahu, or Maui, including methods of excluding or controlling predators, such as predator-proof fences. The cost-effectiveness of various options may differ among sites and should be investigated on a site by site basis. Potential sites include but are not limited to Hanalei and Huleia National Wildlife Refuges on Kauai, James Campbell National Wildlife Refuge on , and Kealia Pond National Wildlife Refuge and Kanaha Pond State Wildlife Sanctuary on Maui.  Conduct research to further investigate demographic parameters that drive population fluctuations and cause differences in clutch size and fecundity on Laysan and Midway, including food and water resources, hatchability, and brood survival.

Laysan Duck profile - 4 October 2012

Hawaiian Bird Conservation Action Plan

 Determine if the avian botulism outbreaks could be reduced at Midway Atoll by eliminating mosquito fish from the managed wetlands.

5-Year Conservation Goals:  Continue management of Laysan Ducks and their habitat on Laysan and Midway.  Establish breeding populations of Laysan Ducks on both and . After Midway, these two islands have been identified as the most suitable sites for establishing populations of Laysan Ducks. Each island would require wetland habitat preparation before it could support Laysan Ducks, and each presents different challenges. Lisianski is Laysan’s nearest neighbor and is known to have previously supported Laysan Ducks, but mammal introductions in the mid-1800s resulted in loss of vegetation cover and shifting sands that filled the island’s wetland. Test pits dug by hand in 2006 had difficulty reaching fresh groundwater and use of heavy equipment would be difficult on this remote island. On Kure, two small freshwater seeps were dug by hand in 2006 and 2007, but additional habitat would be needed, including creation of at least one more wetland or the installation of several 500-gallon artificial wetlands (“Guzzlers”). Control of golden crown-beard (Verbesina encelioides), an invasive alien plant that is used by Laysan Ducks for nesting but is detrimental to nesting seabirds, would need to be controlled before ducks are brought to the island.  Re-establish a breeding population of Laysan Ducks on one of the southeastern Hawaiian Islands.

Conservation Actions:  Establish breeding populations of Laysan Ducks on both Lisianski and Kure.  Habitat management. o Continue to manage wetlands on Midway, including removal of mosquito fish. o Eradicate mice (Mus musculus) from Sand Island, Midway to increase natural recruitment of native bunch grass to ensure availability of quality nesting habitat. o Continue habitat management on Laysan, including removal of alien plants such as Pluchea indica, and restoration of native plants.  Avian diseases. o Respond to any outbreaks of avian botulism that occur by removing dead bird carcasses. o Investigate methods of controlling water level and environmental conditions that can lead to botulism outbreaks on Midway.  Global climate change. Develop feasibility plans for re-establishing a breeding population of Laysan Ducks on Kauai, Oahu, Kahoolawe, or Maui, which are high islands that would provide more of a refuge from rising sea level and storm events.

Summary of 5-year Actions, 2013-2017: Conservation Action Year(s) Annual cost Total Cost Continue habitat management on Laysan, 1-5 $100,000 $500,000 including biosecurity, removal of detrimental alien plants, and restoration of native plants Maintain wetlands on Midway 1-5 $50,000 $250,000

Laysan Duck profile - 5 October 2012

Hawaiian Bird Conservation Action Plan

Respond to botulism outbreaks on Midway 1-5 $30,000 $150,000 Habitat management on Lisianski and Kure to 1-3 $100,000 $300,000 prepare wetland sites for translocation of ducks Translocate ducks to Lisianski 4-5 $250,000 $500,000 Translocate ducks to Kure 4-5 $200,000 $400,000 Investigate feasibility of establishing Laysan 1-2 $30,000 $60,000 Ducks on Kaua’i, O’ahu, Kaho’olawe, and Maui, including methods of predator control or exclusion

Potential Partners: U.S. Fish and Wildlife Service, U.S. Geological Survey Biological Resources Division Pacific Islands Ecosystem Research Center, Papahanaumokuakea Marine National Monument, Division of Forestry and Wildlife, Hawaii Wetland Joint Venture, Ducks Unlimited, Bird Conservation International, American Bird Conservancy.

Ancillary Species: Habitat management on Laysan also would benefit the endangered (Telespiza cantans) and the endangered Millerbird (Acrocephalus familiaris), which was re-introduced to the island in 2011. Management on Laysan and Midway would benefit numerous species of seabirds, migratory waterfowl, and shorebirds, including the (Pterodroma hypoleuca), Hawaiian Petrel (Pterodroma sandwichensis), Bulwer’s Petrel (Bulweria bulwerii), Wedge-tailed Shearwater (Puffinus pacificus), Christmas Shearwater (Puffinus nativitatis), Tristram’s Storm-petrel (Oceanodroma tristrami), White-tailed Tropicbird (Phaethon lepturus), Red-tailed Tropicbird (Phaethon rubricada), (Sula dactylatra), (Sula leucogaster), Red-footed Booby (Sula sula), Great (Fregata minor), Gray-backed Tern (Sterna lunata), (Sterna fuscata), Brown Noddy (Anous stolidus), Black Noddy (Anous minutus), White Tern (Gygis alba), Pacific Golden Plover (Pluvialis fulva), Wandering Tattler (Tringa incanus), Bristle-thighed Curlew (Numenius tahitiensis), and Ruddy Turnstone (Arenaria interpres). On Kaua’i, O’ahu, and Maui, four other species of endangered waterbird would benefit from management directed at the Laysan Duck, particularly predator control or exclusion, including the or Koloa (Anas wyvilliana), Hawaiian Coot or ‘Alae ke‘oke‘o (Fulica alai), the Hawaiian Gallinule or ‘Alae ‘Ula (Gallinula galeata sandvicensis), and the Hawaiian Stilt or Ae‘o (Himantopus mexicanus knudseni).

References: Berkowitz, P., C. D. Storlazzi, K. N. Courtot, C. M. Krause, and M. H. Reynolds. 2012. In Press. Sea- level rise and wave-driven inundation models for Laysan Island. US Geological Survey Report. James, H.F., and S.L. Olson. 1982. Fossil birds of the Hawaiian Islands: Evidence for wholesale extinction by man before western contact. Science 217:633-635. Krause, C. M., K. N. Courtot, P. Berkowitz, J. Carter, and M. H. Reynolds. 2012. In Press. Climate change vulnerability assessment of the low-lying Northwestern Hawaiian Islands. US Geological Survey Report. Marshall, A.P. 1992. Censusing Laysan ducks Anas laysanensis: a lesson in the pitfalls of estimating populations. Bird Conservation International 2:239-251. Moulton, D.W., and A.P. Marshall. 1996. Laysan Duck (Anas laysanensis). No. 242 in the Birds of North America (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA. Moulton, D.W., and M.W. Weller. 1984. Biology and conservation of the Laysan Duck (Anas laysanensis). Condor 86:105-117.

Laysan Duck profile - 6 October 2012

Hawaiian Bird Conservation Action Plan

Olson, S.L., and A.C. Ziegler. 1995. Remains of land birds from Lisianski Island, with observations on the terrestrial avifauna of the northwestern Hawaiian Islands. Pacific Science 49:111-125. Reynolds, M.H. 2004. Habitat use and home range of the Laysan teal on Laysan Island, Hawaii. Waterbirds 27:183-192. Reynolds, M. H., J. H. Breeden, M. S. Vekasy, and T. M. Ellis. 2009. Long-term pair bonds in the Laysan duck. Wilson Journal of Ornithology121:187-190. Reynolds, M. H., K. W. Brinck, and L. Laniawe. 2011. Population estimates and monitoring guidelines for endangered Laysan teal, Anas laysanensis, at Midway Atoll: pilot study results 2008-2010. Hawai`i Cooperative Studies Unit Technical Report HCSU-021, University of Hawai`i at Hilo, Hilo, Hawai`i, 67 pp. Reynolds, M.H., and J.J. Citta. 2007. Post-fledging survival of Laysan ducks. Journal of Wildlife Management 71:383-388. Reynolds, M.H., L.H. Crampton, and M.S. Vekasy. 2007b. Laysan teal phenology and site characteristics on Laysan Island. Wildfowl 57:54-67. Reynolds, M. H., J. S. Hatfield, L. P. Laniawe, P. Berkowitz, M. S. Vekasy, L. H. Crampton, and J. L. Klavitter. 2012. Influence of space use on fitness and the reintroduction success of the Laysan teal. Animal Conservation 15:305-317. Reynolds, M., and J. Klavitter. 2006. Translocation of wild Laysan duck Anas laysanensis to establish a population at Midway Atoll National Wildlife Refuge, and US Pacific Possession. Conservation Evidence 3:6-8. Reynolds, M.H., and K. Kozar. 2000. History and current status of the Laysan duck (Anas laysanensis) in captivity. `Elepaio 60:59-65. Reynolds, M.H., N.E. Seavy, M.S. Vekasy, J.L. Klavitter, and L.P. Laniawe. 2008. Translocation and early post-release demography of the endangered Laysan teal. Animal Conservation 11:160-168. Reynolds, M.H., E. Weiser, I. Jaimeson, and J.S. Hatfield. In Press. Demographic variation and the reintroduction of Laysan Ducks (Anas laysanensis). Journal of Wildlife Management. Reynolds, M.H., and T.M. Work. 2005. Mortality in the endangered Laysan teal: conservation implications. Wildfowl 55:31-48. Rhymer, J.M. 2001. Evolutionary relationships and conservation of the Hawaiian anatids. Pages 61-67 in: Scott, M.J., S. Conant, and C.I. van Riper, eds. Evolution, ecology, conservation and management of Hawaiian birds: a vanishing avifauna. Studies in Avian Biology 22. Cooper Ornithological Society, Allen Press, Inc., Lawrence, Kansas. Seavy, N.E., M.H. Reynolds, W.A. Link, and J.S. Hatfield. 2009. Post-catastrophe population dynamics and density dependence of an endemic island duck. Journal of Wildlife Management 73:414-418. U.S. Fish and Wildlife Service. 2009. Revised recovery plan for the Laysan duck (Anas laysanensis). U.S. Fish and Wildlife Service, Portland, Oregon. Vermeer, M., and S. Rahmstorf. 2009. Global sea level linked to global temperature. Proceedings of the National Academy of Sciences 106:21527-21532. Work, T. M., J. L. Klavitter, M. H. Reynolds, and D. Blehert. 2010. Avian botulism: A case study in translocated endangered Laysan ducks (Anas laysanensis) on Midway Atoll. Journal of Wildlife Diseases 46:499-506. Work, T.M., C.U. Meteyer, and R.A. Cole. 2004. Mortality in Laysan ducks (Anas laysanensis) by emaciation complicated by Echinuria uncinata on Laysan Island, Hawaii, 1993. Journal of Wildlife Diseases 40:110-114.

Laysan Duck profile - 7 October 2012